Technical Field
The present invention relates to an electrophoretic display substrate, particularly, an electrophoretic display substrate capable of performing display inspection by applying a voltage to an electrophoretic display element and allowing whole electrophoretic display elements to be discolored to have a color with a predetermined wavelength using a driving circuit having a simple configuration without mounting a driver IC or a cable in the electrophoretic display substrate, a method of inspecting an electrophoretic display substrate using the same, and an electrophoretic display device.
Background Art
An electrophoretic display substrate which is a display substrate that holds an image even when supply of power to an image display element is cut comes into practical use and is widespread as a display substrate of an e-book or an electronic shelf label. As typical examples of the electrophoretic display substrate which comes into practical use, a microcapsule-type electrophoretic display substrate (manufactured by E lnk, Inc.) and a microcup-type electrophoretic display substrate (manufactured by Sipix, Inc.) are exemplified. In the former case, a liquid obtained by allowing white and black colored particles which are respectively positively and negatively charged to be dispersed in a non-polar and transparent dispersion medium is sealed in a microcapsule, which is used as a display element and is made into a flat display substrate that is arranged on a substrate, on which an electrode is formed, in high density. Meanwhile, in the latter case, countless recesses referred to as microcups are formed in a substrate and a sheet which seals positively or negatively charged colored particles and a non-polar colored liquid in the recesses is used in application as a flat display substrate.
In both systems, an electrophoresis phenomenon in which colored particles are moved by applying a voltage to the charged colored particles due to an electrostatic attraction force is used, and the display substrate has a holding property of an image by the moved colored particles remaining in the moved place even when the application of a voltage is stopped.
Since the color of an image which can be displayed by these electrophoretic display substrates is determined by a combination of colors of charged colored particles or colored liquid, it is necessary to display a full color image using a mixture of colors with three primary colors such as red (R), green (G), and blue (B) or cyan (C), magenta (M), and yellow (Y) in order to display a full color image. At this time, a region displaying a color of three primary colors such as R, G, and B is referred to as a sub pixel, and a combination of sub pixels of three primary colors is referred to as a color pixel. The color pixel having the smallest number of sub pixels among combinations of sub pixels constituting a color pixel is a color pixel formed of three sub pixels including one sub pixel of R, one sub pixel of G, and one sub pixel of B.